This counter tracks how many SCSI busy statuses this specific port has sent or received, and per the desc the direction depends on the port's role - initiator ports only ever receive busy statuses, while target ports only ever send them. An admin monitoring a target port on a storage array watches this counter to gauge how often that specific port is telling initiators it is too busy to accept new commands, a sign that port (rather than the whole array) is becoming a bottleneck. A single target port on an array showing much higher busy-status counts than its sibling ports would suggest traffic is not evenly balanced across the array's front-end ports.